too long

my form is form method="post">

input type="checkbox" name="facebook" value="yes">

Submit

So, what I want to do is:

a) If the checkbox is checked, I want to update the appropriate field with yes

b) If the checkbox is unchecked, I want to update the field with no

$_POST['chk_ans'] will return only when it is being checked,

if (isset($_POST['chk_ans']))
{

..Update Query here ..

}

Using this form:

<form method='POST'>
    <input type='checkbox' name='myCheckbox' />
    <input type='submit' name='submit' value='Submit' />
</form>

You could handle it this way serverside:

<?php
    $mysqli = new mysqli("localhost", "myUser", "myPassword", "myDb");

    if(isset($_POST['submit'])) {
        $value = $_POST['myCheckbox'] ? 1 : 0;
        $mysqli->query("UPDATE myTable SET myTinyInt = " . $value);
    }
?>

Firstly you want to have everything ready in sql, a table that you want values to go into, and procedures you want to make for this to work, You may want to make a insert procedure and a update procedure. You then want to call the method so that your values can be added into sql.

Try this:

<?php

            // You'll need a connection to db, in my example (mysql connection) this is not included.

            // Check if form has been submitted.
            if($_SERVER['REQUEST_METHOD'] == 'POST') {

                $field = (isset($_POST['facebook']) AND $_POST['facebook'] == 'yes') ? 'yes' : 'no';

                // Your query: In this example for mysql extension
                mysql_query('UPDATE my_table SET field="'.mysql_real_escape_string($field).'"');

            }

        ?>